Does anybody know of any places of practice or 'Physical' churches within the United Kingdom? More specifically, England.

There are no such "churches", nor is there any need for them. Here's a quote from the Affiliation page of the official Church of Satan website:

"...We thus do not maintain any church structures nor are our Central offices open to visitation by the public. It is therefore pointless to ask for an address of a local Church of Satan. Read this essay to grasp the unique way in which our organization functions. Non-members may not attend rituals (which are by nature private activities held in the homes of members), regardless of their degree of interest or reason for wishing to participate. There are no exceptions to this policy."